In late 1991, conservative commentator Patrick Buchanan launched his candidacy for the Republican presidential nomination, challenging incumbent Republican president George H.W. Bush. The former Nixon speechwriter’s candidacy was built on a snarling call for a “religious war” in America, and an appeal to those on the ultra-right to join him in hating those different from them. A quarter century before Donald Trump took Buchanan’s hand-off and rode a wave of social rage into the White House, Pat Buchanan understood that ugliness has a constituency, and he knew where and how to locate it.

Part of Buchanan’s appeal was to the anti-Semitic impulse residing in certain American quarters, a pitch too frequently made and too obvious to ignore. When Saddam Hussein invaded Kuwait and an international coalition of over 30 countries, including Arab and other Muslim nations, joined the United States in coming to Kuwait’s aid, Buchanan blamed it on the Jews. “There are only two groups that are beating the drums for war in the Middle East,” Buchanan asserted, entirely falsely, “the Israeli Defense Ministry and its amen corner in the U.S.”

The father of modern American conservatism, the late William F. Buckley Jr., felt morally compelled to go on record that being a conservative was one thing, and being a bigot quite another. “I find it impossible to defend Pat Buchanan against the charge that what he did and said during the period under examination amounted­ to anti-Semitism,” Buckley wrote in the National Review, the conservative journal he had founded.

Massachusetts Republicans are presented with a golden opportunity this September to deliver a similar message — that they will neither endorse nor be associated with bigotry, and that there is a difference between being a conservative and being unhinged. The opportunity will come in the state’s GOP primary, in which incumbent Gov. Charlie Baker finds himself pitted against pastor Scott Lively. The primary is occurring only because 28 percent of the delegates to last month’s Republican state convention voted for Lively, whose claim to fame is blaming Nazism on homosexuals.

That’s right: Lively, who has called for the criminalization of “homosexual advocacy,” is the co-author of a thoroughly discredited book called “The Pink Triangle,” which accuses the LGBTQ community of culpability for the Third Reich. This is, to put matters mildly, revisionist history, veering from the bizarre to the un­tethered, among other things, because homo­sexuals were actually among the Nazis’ ideological targets.

Lively occupies a netherworld of extremists. “Homo­sexuality is a personality disorder that includes various, often dangerous, sexual addictions and aggressive anti-social impulses,” he has written, positioning himself somewhere between the paleolithic era and the 17th century. A federal judge in Massachusetts has described Lively as the promoter of “crackpot bigotry.”

The contrast between Lively and Charlie Baker could not be more stark. Baker is one of the bright spots of the Republican Party, combining real decency and an adherence to values that by rights ought to win the approval of principled Republicans. His vetoes of legislative earmarks, pursuit of private-public partnerships as an alternative to purely taxpayer-funded programs and proposals for tougher penalties for assault and battery against police officers, along with his tight-fisted management of governmental budgets, would seem to qualify him for the support of rank-and-file Republicans. On the subject of Lively’s wooing of rock-dwellers, Baker has been clear as a bell. “There is no place and no point in public life, in any life,” Baker­ has said, “for a lot of the stuff Scott Lively says and believes.”

Baker has a promising political career yet ahead of him, and deservedly so. When it is eventually over, he will be remembered as an honorable public servant. Scott Lively will be remembered as the lightest of lightweights, who got five minutes of attention because he personified some of the worst ugliness of our time — if he is remembered at all.

Jeff Robbins is a Boston attorney and former U.S. delegate to the United Nations Human Rights Commission.